Method of protecting metal surfaces against abrasive wear in pumps with polyquaternaries

ABSTRACT

SOLUTIONS OF WATER SOLUBLE AND/OR DISPERSIBLE POLYQUATERNARY, POLYMERIZED, OXYALKYLATED AMINES NOT ONLY OFFER PROTECTION AGAINST ABRASIVE WEAR TO SUBMERGED METAL SURFACES, SUCH AS IN SUBMERSIBLE OIL WELL PUMPS, BUT ALSO THROUGH THEIR ANTI-BACTERIAL AND CORROSION INHIBITING ACTION OFFER PROTECTION AGAINST CORROSIONS AND BACTERIAL DETERIORATION OF THE PUMP. IN ADDITION, BECAUSE OF INCREASED WATER VISCOSITY, THEY ALSO REDUCE FOAMING AND CAVITATION DURING PUMPLING.

United States Patent.

3,751,364 METHOD OF PROTECTING METAL SURFACES AGAINST ABRASIVE WEAR IN PUMPS WITH POLYQUATERNARIES Thomas J. Bellos, Kirkwood, Mo., assignor to Petrolite Corporation, Wilmington, Del.

No Drawing. Filed Apr. 15, 1971, Ser. No. 134,457 The portion of the term of the patent subsequent to May 9, 1989, has been disclaimed Int. Cl. C10m 1/18, 1/32 US. Cl. 252-493 6 Claims ABSTRACT OF THE DISCLOSURE In recent years hydraulic pumping systems for oil wells have gone into widespread commercial use. These systems utilize subsurface pumps which are positioned within the oil well casing near the production stratum. The moving parts of these pumps operate with very close tolerances, and the problem of abrasive wear is severe, especially when a brine or saline solution is employed. Brines are not ordinarily usable as hydraulic fluids because of their corrosive nature.

Chemical agents for use in lubricating submersible oil well pumps should be water-soluble or dispersible so that they can be introduced into the aqueous hydraulic fluid at the surface of the well, and the chemical agent must be absorbed on the metal surfaces to be lubricated as the hydraulic fluid circulates over these surfaces. The chemical agent, after adsorption on the metal surfaces, must function as a highly effective lubricant, that is, it must reduce abrasive wear between the surfaces. The lubricant should also have the property of remaining on the metal surfaces under a high applied pressure or torque, as would be generated between the relative moving metal surfaces of the pumps. In other words, the lubricant should have good boundary properties to minimize wear and to prevent any increase in the tolerances of the contacting parts, and it should also be effective as an extreme pressure lubricant so that it is not squeezed off of the surfaces or desorbed at torques of greater than 60 to 80 inch-pounds.

In oil production there exists a great number of solutes which are very corrosive to the submerged pumps, for example, salts such as NaCl, CaCl BaCl sulfates of such metals and gases, such as H 8, which are very corrosive to the metals commonly used in oil, water and gas production. In addition to corrosion, damage is also caused by bacteria, which attack the metal surface of the pumps and in so doing produce colonies of bacteria (black slime) and hydrogen sulfide, which is the product of the bacteria, attack on the metal surface. Both bacterial attack and H 8 destroy the metal. Thus an ideal subsurface pump lubricant, or more properly stated a pump protectant, is one that not only lubricates the metal parts but also protects against corrosion including that resulting from bacterial attack on the metal construction of the pump. Formulations which afford both lubricating and anti-bacterial action are ordinarily achieved by using individual ingredients each of which does a particular job. However, the use of a sole agent which would perform both functions would have a definite advantage over formulations containing multiple components.

3,751,364 Patented Aug. 7, 1973 In addition to corrosion and bacterial inhibition, the lubricant should not precipitate or oil out (i.e., float to the top) in hard water. Since many lubricants are surface active in nature, they also tend to reduce the surface tension of water, thus causing foaming and cavitation, i.e., a reduction in pumping due to foaming particularly in the pump pressurizing chamber.

I have now discovered that solutions of water soluble and/or dispersible poly-quaternary, polymerized, oxyalkylated amines not only offer protection to submerged metal surfaces, such as in submersible oil well pumps, against abrasive wear but also offer, through their antibacterial and corrosion inhibiting action, protection against deterioration of the pump due to corrosion and bacterial action.

In addition, the compositions of this invention reduce the tendency toward foaming and cavitation since they tend to increase the viscosity of the water.

Stated another way, the compositions employed as lubricants in this invention not only exhibit good lubricating, corrosion and bacterial protection, but they also increase water viscosity so as to reduce cavitation. They also resolubilize certain inorganic salts associated with oil field waters such as, for example, MgSO CaSO etc.

The compositions of this invention are amines which have been reacted as follows:

(1) Oxyalkylation.

(2) Dehydration or polymerization by removal of water so as to join at least two oxyalkylated molecules with the formation of an ether linkage thus increasing the molecular weight.

(3) Quaternization of the amino groups.

Stated another way, the molecular weight of oxyalkylated amines is increased by etherification due to dehydration or polymerization and the higher molecular weight oxyalkylated amines are then quaternized. These are illustrated by the following reactions:

A (where O is an alkylene oulde and R is a hydrocarbon group) R R -H 0 HOA(OA),.N(AO),.AO I H H0 A(OA)DN(AO)HAOH 2 Two of these molecules can be further dehydrated similarly to double the molecular weight, and this is continued sequentially until the desired molecular weight is obtained. For convenience this polymerized product may be expressed by the following idealized formula:

This polymeric oxyalkylated amine is then quaternized with a suitable reagent such as an alkyl halide (R'X) to yield a quaternized polymer, idealized as follows:

for example cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, etc.; substituted derivatives thereof, for example alkyl or polyalkyl, for example alkyl cyclohexyl, dialkyl cyclohexyl, etc.

Aryl

These include phenyl, substituted penyl, alkyl, phenyl, polyalkylphenyl, chlorophenyl, alkoxyphenyl, etc., naphthyl, alkyl naphthyl, etc.; benzyl, substituted benzyl, etc., groups.

Heterocyclic These include furyl, pyranyl, hydrogenated furyl, pyranyl, etc., groups.

Representative commercial amines are available, for example, those shown in the preceding table.

The nomenclature of these amines is derived from either their chain length or source of raw material, for example,

Armeen 8D-Octyl amine Armeen CCoconut oil amine Armeen S--Soybean oil amine Armeen TTallow amine Armeen OOleyl amine Armeen HTHydrogenated tallow amine Products with D designate distilled grade. Products without D designate technical grade.

Polymerization through dehydration of oxyalkylated amines The oxyalkylated products described herein can be heat treated to increase the molecular weight.

In general, the heat treatment is carried out at 200- 250" C. Under dehydrating conditions, where reduced pressure and a fast flow of nitrogen is used, lower temperatures can be employed, for example, ISO-200 C.

Water is removed during the reaction, such as by means of a side trap. Nitrogen passing through the reaction mixture and/or reduced pressure can be used to facilitate water removal.

The heat treatment results in the polymerization of these compounds and is effected by heating same at elevated temperatures, generally in the neighborhood of ZOO-270 C., preferably in the presence of catalysts, such as sodium hydroxide, potassium hydroxide, sodium ethylate, sodium glycerate, or catalysts of the kind commonly employed in the manufacture of superglycerinated fats, calcium chloride, zinc chloride, iron and the like. The proportion of catalyst employed may vary from slightly less than 0.1%, in some instances, to over 1% in other instances.

Conditions must be such as to permit the removal of Water formed during the process. At times the process can be conducted most readily by permitting part of the volatile constitutents to distill, and subsequently subjecting the vapors to condensation.

The condensed volatile distillate usually contains water formed by reaction. The water can be separated from such condensed distillate by any suitable means, for instance, distilling with xylene, so as to carry over the water, and subsequently removing the xylene. The dried condensate is then returned to the reaction chamber for further use. In some instances, condensation can best be conducted in the presence of a high-boiling solvent, which is permitted to distill in such a manner as to remove the Water of reaction. In any event, the speed of reaction and the character of the polymerized product depend not only upon the original reactants themselves, but also on the nature and amount of catalyst employed, on the temperature employed, the time of reaction, and the speed of water removal, i.e., the effectiveness with which the water of reaction is removed from the combining mass. Polymerization can be effected without the use of catalysts in some instances, but such procedure is generally undesirable, due to the fact that the reaction takes a prolonged period of time, and usually a significantly higher temperature. The use of catalyst such as ZnCl etc., fosters the reaction.

Alkylation Alkylation relates to the reaction of polymerized oxyalkylated amines with alkylating agents.

Any hydrocarbon halide, e.g., alkyl, alkenyl, cycloalkenyl, aralkyl, etc., halide which contains at least one carbon atom and up to about thirty carbon atoms or more per molecule can be employed to alkylate the products of this invention. It is especially prefered to use alkyl halides having between about one to about eighteen carbon atoms per molecule. The halogen portion of the alkyl halide reactant molecule can be any halogen atom, i.e., chlorine, bromine, fluorine, and iodine. In practice, the alkyl bromides and chlorides are used, due to their greater commercial availability. Non-limiting examples of the alkyl halide reactant are methyl chloride; ethyl chloride; propyl chloride; n-butyl chloride; sec-butyl iodide; tbutyl fluoride; n-amyl bromide; isoamyl chloride; n-hexyl bromide; n-hexyl iodide; heptyl fluoride; Z-ethyI-hexyl chloride; n-octyl bromide; decyl iodide; dodecyl bromide; 7-ethyl-2-methyl-undecyl iodide; tetradecyl bromide; hexadecyl bromide; hexadecyl fluoride; heptadecyl chloride; octadecyl bromide; docosyl chloride; tetracosyl iodide; hexacosyl bromide; octacosyl chloride; and triacontyl chloride. In addition, alkenyl halides can also be employed, for example, the alkenyl halides corresponding to the above examples. In addition, the halide may contain other elements besides carbon and hydrogen, as, for example, where dichloroethylether is employed.

The alkyl halides can be chemically pure compounds or of commercial purity. Mixtures of alkyl halides, having carbon chain lengths falling Within the range specified hereinbefore, can also be used. Examples of such mixtures are mono-chlorinated wax and mono-chlorinated kerosene. Complete instructions for the preparation of mono-chlorowax have been set forth in United States Pat. 2,238,790.

Thus, the term alkylation as employed herein and in the claims include alkenylation, cycloalkenylation, aralkylation, etc., and other hydrocarbonylation as well as alkylation itself.

The following examples are presented by way of illustration and not of limitation. Oxylakylations are conventional.

TABLE B Alkylene oxides Example Amine (moles) Oleyl amine C1aHa5NHa PrO (l) EtO (l) .-dO.-- PrO (2) E (1) 3 do EtO (2) NOTE.Examples 1-10 employed Armeen 0; Example 11 employed Armeen '1.

All of the above oxyalkylated. amines were polymerized by heat treatment according to the following procedure.

POLYMERIZATION EXAMPLES The amine ethoxylates are changed to a glass round bottom reaction flask outfitted with heating mantle, stirring motor, Dean & Stark trap and condenser and thermometer, and heated to 50 C.., after which 1-5 gms. ZnCl (powdered) are added. All air is swept from the flask and stirring commenced. While heating and stirring the temperature is gradually increased to 110 C. (half-hour) at which time water of condensation begins to come off. Heat is continued until an ultimate 245 C. is obtained. Water of reaction removed does not come off at any particular rate, however, when the Water of reaction starts to subside, the product shows increasing viscosity. After 8 hours the reaction is stopped and allowed to cool while stirring. Products are bright and viscous warm, somewhat hazy on cooling.

All of the above polymerized oxyalkylated amines were quaternized according to the following procedure.

QUATERNIZATION EXAMPLES .Alkylene oxide modified amine polymers are changed into an autoclave or suitable reaction vessel. A 50/50 blend of 2-propanol and Water is added or in the case of some high boiling alkyl halides, they are run without solvent, in an amount which will theoretically yield a 40% solution of amine. The quaternizing agent is then added, i.e., when methchloride is used excess reagent is added to yield an exhaustive quaternization as excess is easily removed because of its low boiling point. The mixture is then heated to 140 C. until no change in pressure is observed, indicating that all methylchloride that will react has done so. In the case of high molecular weight alkyl halides, they are reacted on a mole-to-mole basis for a period of 24 hours at 150 C., i.e., benzyl chloride.

The following quaternizing agents were employed with the above polymerized products.

USE EXAMPLES In practicing the method of this invention, the lubricating compound is dissolved or dispersed in water or in a saline brine, or more generally in the aqueous phase of a fluid medium, which may consist of an oil and brine mixture, or a pumpable drilling mud having an aqueous phase, etc. The concentration of the lubricating agent in the water or the aqueous phase of the fluid medium should be suflicient to provide for the coating of the met-a1 surfaces to be protected against abrasive wear. Usually, the water of aqueous phase should contain at least 50 p.p.m. (parts per million) of the lubricating compound, and in most applications, it will usually be preferable to employ at least 80 p.p.m. of the lubricating compound. Usually, it will not be necessary or desirable to use concentrations greater than 500 to 1000 p.p.m. For use in oil well subsurface pumps where the lubricating compound is introduced into the brine employed as the hydraulic fluid, concentrations of from 50 to 500 p.p.m. are satisfactory. For example, good results have been obtained in such applications with concentrations ranging from 100 to 200 p.p.m. The aqueous phase containing the lubricating compound is contacted with, or preferably circulated over, the metal surface to be protected against abrasion. If desired, the surface may be continually treated with the water or aqueous phase containing the lubricating compound, thereby tending to maintain the desired protective layer or film of the lubricating compound during operation of the pump or similar apparatus.

The method of this invention is further illustrated by its application to the lubrication of subsurface hydraulic pumps in oil well production operations. The oxyalkylated quaternary ammonium compound is employed as a lubricant in the aqueous power fluid at a concentration of from 150 to 200 p.p.m. The power fluid may be salt water or fresh water. Before circulation to the subsurface pump, the power fluid will be kept in one or more surface tanks, and is therefore convenient to introduce the lubricating agent into the fluid While it is under surface storage. For a so-called open system the fluid will only be circulated once, and therefore it is a simple matter to achieve the desired concentration introducing the lubricating agent into the fluid before it is circulated. For a closed system where the aqueous hydraulic fluid is recirculated after it has been separated from the oil, there may be some residual lubricating agent in the fluid, and it may be desirable to add only sufficient lubricating agent to make up the concentration to the desired level before the fluid is recirculated. Alternatively, a higher than necessary concentration can be employed for the initial circulation, such as a concentration of 500 to 600 p.p.m., and the fluid can be recirculated until the concentration drops below the desired level for maximum lubricating protection. With this procedure, make-up lubricating agent need only be added periodically. In addition practice dictates that oxygen scavenging agents be incorporated in these solutions to remove dissolved oxygen which is extremely corrosive to submerged pumps. Typically, hydrazine 35% solution and sodium sulfite are used. The latter is used in wells below F. and hydrazine in the above 100 F. wells. If desired, an auxiliary corrosion inhibitor can also be incorporated in the circulating fluid. The procedure just described is applicable to various commercial subsurface pumps, such as those supplied by the Fluid Packed Pump Company, a division of the National Supply Company, or by Kobe, Inc.

While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof and many details have been set forth for the purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to other applications and embodiments and that many of the details described herein can be varied considerably Without departing from the basic principles of the invention.

The compositions of this invention are employed in fluids which are in contact with metal surfaces brought into abrasive wear contact. Thus, this invention is not limited to subsurface pumps alone but also includes those applications where any pump is used to direct an aqueous fluid, such as in sealed hydraulic systems or any system where fluids such as an aqueous solution, or partially aqueous system containing some oil, etc., is pumped.

Having thus described my invention, what I claim as new and desire to obtain by Letters Patent is:

1. The process of simultaneously lubricating and protecting metal surfaces brought into abrasive wear contact against corrosion and bactericidal action in water or a saline brine in contact with said metal surfaces in abrasive wear contact characterized by adding to said water or saline brine a polyquaternary polymerized amine salt formed by oxyalkylating a monoamine of the formula where R is alkyl of 1-50 carbon atoms, alkenyl of 2-50 carbon atoms, alkinyl of 2-50 carbon atoms, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, alkyl derivatives of said cycloalkyls, polyalkyl derivatives of said cycloalkyls, phenyl, polyalkylphenyl, alkyl phenyl, chlorophenyl, alkoxyphenyl, naphthyl, alkyl naphthyl, benzyl, furyl, pyranyl, hydrogenated furyl, or hydrogenated pyranyl.

with alkylene oxide selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, amylene oxide, octylene oxide, styrene oxide, methyl-styrene oxide, cyclohexene oxide, and mixtures thereof, to form an oxyalkylated amine, then polymerizing said so-formed oxyalkylated amine by removal of water so as to ioin at least two oxyalkylated molecules with the formation of an ether linkage thereby increasing the molecular weight, and then reacting said so-formed polymerized oxyalkylated amine with an alkyl, alkenyl, cycloalkenyl or aralkyl halide,

where said alkyl, alkenyl, cycloalkenyl or aralkyl has 1-30 carbon atoms, mixtures thereof, or dichloroethyl ether, thereby to quaternize said so formed polymerized oxyalkylated amine.

2. The process of claim 1 where R of said monoamine having the formula R-NH-z has 1-30 carbon atoms.

3. The process of claim 2 where the alkylene oxide is ethylene oxide, propylene oxide, butylene oxide or mixtures thereof and said so-formed polymerized oxyalkylated amine is reacted with methyl chloride, ethyl chloride, butyl chloride, hexyl chloride, benzyl chloride, dichloroetyl ether or morn-Q-omcr 4. The process of claim 6 where said so-formed polymerized oxyalkylated amine is reacted with methyl chloride.

5. The process of claim 3 where R has 12-18 carbon atoms and the alkylene oxide group is present in said oxyalkylated amine prior to polymerization in the amount of 1-10 alkylene oxide units.

6. The process of claim 5 where R-NH is C H NH and said so-formed polymerized oxyalkylated amine is reacted with methyl chloride, ethyl chloride, butyl chloride, hexyl chloride, benzyl chloride, dichloroethyl ether DANIEL E. WYMAN, Primary Examiner W. J. SHINE, Assistant Examiner US. Cl. X.R. 2525l.5 R, 392 

